Multi-layer wiring board substrate and semiconductor device using the multi-layer wiring substrate

摘要

A multi-layer wiring substrate comprises: a plurality of wiring substrates, each of the substrates comprising a plate or sheet-like insulating layer and a wiring layer formed on only one of surfaces of the insulating layer; the plurality of wiring substrates being laminated in such a manner that the insulating layer and wiring layer are alternately arranged; at least a pair of said wiring layers arranged on respective surfaces of the insulating layer being electrically connected with each other by means of connecting portions formed so as to pass through the insulating layer; and the connecting portion comprises a part of the wiring layer which is extended into a region of an opening formed so as to pass through said insulating layer and a low-melting point metal disposed in the opening and electrically connecting the part of the wiring layer with a wiring substrate formed on an adjacent insulating layer of the laminated structure.